Bike Tools

Power-to-speed estimator, climb calculator, and gearing calculator.

Power ↔ speed

Solve for

Power (W)

Rider + bike (kg)

Gradient (%)

Position

Model: rolling resistance (Crr 0.004) + aero drag (air density 1.225 kg/m³) + gravity, with 2.5% drivetrain loss. Assumes still air and a steady effort.

Climb calculator

Length (km)

Avg gradient (%)

Power (W)

Rider (kg)

Bike + kit (kg)

Same physics model, climbing position (CdA 0.32). VAM is vertical metres climbed per hour.

Gearing

Chainring (T)

Cog (T)

Wheel / tyre

Cadence (rpm)